IMPORTANT WESTERN BROWSE PLANTS O1 
mortality being among pregnant ewes. The species evidently has 
active chemical properties and would well repay a thorough scien- 
tific study. Numerous medicinal uses of the plant are reported (78, 
75, 118). It is also locally employed in making an amalgam, glue, 
or cement (13), as a substitute for shellac and cochineal, and as a 
hedge plant. The highly inflammable nature of the bush (which 
burns with a bright blaze, heavy smoke, and penetrating, creosotelike 
odor) makes it something of a fire hazard. 
RUE FAMILY (RUTACEAE) 
This is the family to which the various oranges (Citrus aurantium, 
nobilis, sinensis, etc.), citron (C. medica), grapefruit (C. grandis, 
syn. C. maxima weacarpa), lemon (C. limonia), and lime (C. 
aurantifolia) belong. 
Starleaf (Chowya dumosa, syn. Astrophyllum dumosum) (fig. 24), 
known also as Mexican-orange and, to Mexicans, as sorilla and 
zorillo, is a low, rather bizarre-looking shrub, with thickish stems 
and rather slender twigs, warty roughened with glands. It is found 
from western Texas to southern Arizona, Chihuahua, and Coahuila, 
growing in dry, sandy, gravelly, or rocky situations, on hillsides, in 
(often very rough) canyons and arroyos, between about 4,000 and 
6,500 or 7,000 feet, 1. e., chiefly in the pinon-juniper belt, or Upper 
Sonoran zone, usually occurring as scattered individual plants. 
The gland-toothed leaflets of this shrub have a peculiar, bitter 
aromatic taste, somewhat reminiscent perhaps of its relatives the 
citrus fruits. Ordinarily it does not seem to be touched by livestock, 
but in southern New Mexico it has been considered poisonous to 
goats, as possibly causing a kidney disease. There is no direct proof, 
however, that starleaf is responsible for goat losses. 
HOPTREES (PTELEA SPP.) 
This genus, known also as shrubby trefoil and wafer ash, is con- 
fined to the United States and Mexico; there are perhaps two or 
three species of it in the Southwest, growing as shrubs or small trees 
among rocks, in canyons, sandy flats, and the lke, mostly below 
6,000 feet elevation. Botanists differ widely as to the number of 
valid species of Ptelea. About 70 species have been described and 
the nomenclature in consequence is much confused. The twigs have 
a bitter taste and the trifoliolate leaves have in most forms a dis- 
agreeable odor; livestock, under normal conditions, leave these plants 
alone. The bark, leaves, and roots of hoptrees have bitter-tonic 
properties and are employed in medicine. The vernacular name 
refers to the use of the winged, waferlike fruits as a substitute for 
hops in making beer. Common hoptree (P. trifoliata) is often culti- 
-vated as an ornamental. 
DESERT-RUES (THAMNOSMA SPP.) 
Desert-rue is represented by two glandular, strong-smelling shrubs 
or undershrubs of the Southwest, unpalatable to grazing animals. 
Mohave desert-rue (Thamnosma montana), often called turpen- 
tine broom and, by Mexicans, cordoncillo, with smooth, green, almost 
leafless, broomlike stems, is a familiar desert shrub occurring from 
